1. Field of the Invention
The present invention relates, generally, to a vacuum generator and, more specifically, to a method for operating a vacuum generator with pressure fluid for generating vacuum.
2. Description of Related Art
Vacuum generators for operating vacuum handling devices such as gripping or clamping devices are known, for example so-called ejectors that are operated with compressed air and provide a vacuum in a suction point on the basis of a supply of compressed air. Vacuum can be generated with ejectors from a stream of compressed air, such as with a Venturi nozzle. In the following context, a pressure appearing in the suction point below ambient pressure will be referred to as vacuum. In operating the vacuum generator, it is known to supply compressed air non-continuously, deactivating the supply during particular time periods. Moreover, it is known to monitor the vacuum generated in the suction point and to employ it for control of the vacuum generator. The supply of compressed air for generating vacuum can then be activated and deactivated in dependency on the vacuum prevailing in the suction point. This makes it possible to reduce the compressed air consumption of the vacuum generator in operation with the vacuum handling device by deactivating the supply of compressed air when the vacuum reaches a hold value in the suction point. Activation can then take place again when the vacuum in the suction point has risen to a standard value (for example due to leakage).
It is desirable to monitor the energy consumption when operating vacuum generator, as low energy efficiency leads to undesired costs. Moreover, utilization of additional measuring equipment in the vacuum system can lead to leakage or susceptibility to errors. Thus, there remains a need in the art for reliable monitoring of the energy efficiency for vacuum generators.